This invention relates to a device for indicating the readiness or operation of laser medical instruments, such as instruments used in ophthalmology, which is an important field of use of laser instruments.
For example, when treating a cataract in the eye, protein fibrils which cause a clouding of the lens or vitreous body of the eye are to be destroyed. For this purpose, it is preferable to use lasers which emit a chain of pulses when a given pump light energy is reached, the chain of pulses consisting of a plurality of individual pulses which, when focused, produce a spontaneous ionization of matter.
Patients have reported that the high laser outputs, they feel a pressure in the eye when the laser pulses impinge thereon, but the pressure is not considered painful. In order to prevent the patient from establishing a relationship between the indication of readiness for operation of the laser and the perception of pressure in the eye, and possibly reacting thereto, it is desirable that the signal or indication of readiness for operation of the laser be not perceptible to the patient, but only to the doctor. The present invention accomplishes this.
Indicating devices are known in the art, which indicate that the treatment laser is ready or operation by giving an optical signal i.e., a visible indication such as a pilot light. One such device is disclosed, for instance, in German Federal Republic Offenlegungsschrift (unexamined patent application) No. 28 32 847, of J. Eichler et al., published Feb. 14, 1980, International Class A61B 17/36. This device has the disadvantage that the treating physician must shift his glance from the operating field to the indicating device in order to be informed when the laser is ready for operation, and this disturbs his concentration on the operating field.